The following description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
As the demand for transmission of high quality content across the cellular network increases, the need for better large-scale cellular antennae that support higher capacity rises. The commonly used sector antenna designs have several drawbacks. First, there is a limited number of ports allowed per sector. Second, sector antenna has marginal pattern and beam performance (e.g., poor isolation between beams in the case of multi-beam antennas, side lobes, etc.).
It has been proposed that using a spherical lens (e.g., a Luneburg lens, etc.) along with radio frequency transceivers can provide better result than traditional sector antenna. For example, U.S. Pat. No. 5,821,908 titled “Spherical Lens Antenna Having an Electronically Steerable Beam” issued to Sreenivas teaches an antenna system capable of producing independently steerable beams using a phased array antenna and a spherical lens. U.S. Pat. No. 7,605,768 titled “Multi-Beam Antenna” issued to Ebling et al. discloses a multi-beam antenna system using a spherical lens and an array of electromagnetic lens elements disposed around the surface of the lens.
However, these antenna systems are not suitable for base station antennae. Thus, there is still a need for effectively utilizing spherical lens in a base station antenna application.
All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.